Navigating instrument



Sept. 1, 1931. H. ADDISON ET AL NAVIGATING INSTRUMENT Filed Sept. 6.1927 4 Sheets-Sheet l HERBERT A ILLI M BLAINE L DDISON, UAR 1), @Am,

(Dior/um Sept. 1,1931. H. ADDISON ET AL NAVIGATING INSTRUMENT FiledSept. 6, 1927 4 Sheets-Sheet 2 g I 34. I ,w

004014. Hsgssn'rflpplsou; LLIHM L NE UARD P 1931- H. ADDISON ET AL1,321,870

NAVIGATING INSTRUMENT Filed Sept. 6, 1927 4 Sheets-Sheet 3 HERBERTAmuse/v, F/ G. WILLIAM BLAINELUAR-D,

Sept. 1,1931. H. ADDISON ET AL 1,821,870

NAVIGATING INSTRUMENT Filed Sept. 6, 1927 4 Sheets-Sheet 4 :m the line4--4 of Fig.

:3 -Fig.

' Patented 1, 1931 nannna'r nn'msoxr. or WOBTHING,

AND BLAINE LUARD, 0F FAELMO'UTH,

ENGLAND navma'rme inseam-mam Application filed September 6,

This invention relates to navigating instruments, and has for its objectnew and improved instrument of this kind particularly applicable toaircraft.

The instrument according to this invention ismore particularly adaptedfor determining the direction and velocity of the wind by an observer inan aeroplane or airship, but is also adapted for solving various otherproblems of an analogous nature, or dependent upon the determinations ofthe said factors. In all cases the factors which are to be determinedmay be read ofi, after the necessary initial adjustments have been made,immediately and simultaneously from the scales provided on theinstrument without any necessity for makingcalculations.

In order that the nature of the invention may be clearly understood,embodiments of the same are illustratedin-the accompanying drawings, inwhich:

Fig. 1 is a top plan view of an instrument in accordance with theinvention, the cover of which is removed;

Fig. 2 is a part section on Fig. 1; i

Fig. 3 is a top plan view of a modified form of the instrument shown inFig. 1;

Fig. 4 is an elevatigh partly in SBCtlOKl' on 9 Fig. 5 is a sectionalelevation on the line 5-5 of Fig.3; Fig. 6 is a top plan view of anothermodification of the instrument shownin 1.;

7 is an elevation partly in section on the line 7-7 of Fig. 6, the armsbeing supposed, for the sake of clearness, to be all turned into theplane 77;

Fig. 8 is an inverted plan view of certain parts shown in Figs. 6 and 7.

Referring to Figs. I the instrument illustrated consists of a circularbase a in tlie form of a shallow clip-shaped part having a flangd edge.circumm ferentially moving saddles or b, and

to provide a.

the line 2-2 oi.

cursor Z which 1 and 2 ofthe drawings,

1927, Serial H0. MMOB and in Great Britain September 8, 1926.

5 are arranged to slide upon the'raised upper edge of the-base a, andthese saddles or slides may be locked in any'desired circumterentiallposition, by the clamping screws 0, c and 0 respectively.

Each of thesaddles b, b, b has an arm projecting radially inwards asindicated at d, cl, 0Z respectively. Each of the two arms, (Z, d carriesa slider or cursor e, 6 respectively, which can be locked in anyposition along the arm by its clamping screw 7, or f. Pivoted to thecursor e is a blade or auxiliary arm g while a similar blade g ispivoted to the cur-- sor e", both of the blades 9 and g being capabio ofangular movement relatively to the cursors and each being provided witha clamping screw, as indicated at it and h.

.Two additional arms m and g are connected by a pivot p to the centre ofthe base a, the outer ends of the arms on and 9 being preferablysupported by grooves formed in the internal surface of the rim of thebase a, as shown on the right of Fig.3. The arm m can be lockedin anydesired radial position by a clamping screw n, and carries a can belocked in any desired position upon the arm by clamping screw is.

Arm gis provided with a cursor 1' andarm d with a cursor s. the threecursors Z, s and 1- on their respective arms m, d and q is determined bymeans of the pantograph t which is pivotally connected to the said threecursors in the manner shown in our co-pending patent application No.135,688 filed on the 15th September 1926. In the form shown theinstrument is adapted for the navigation of aircraft, and the three arms01, d and g are therefore graduated in units of air speed, while arm nis graduated'in units of wind speed and arm d in units of ground speed.The cursors e and c are raduated in degreesof drift angle.

T e upper face, of the outer, ange of base a is graduated in degreessimilarly as in the case of a compass card,- and similar gradua- Therelative position of good from the tions are formed on the verticalinner face of the rim of the said base a, while the points of thecompass (N. E. S. W. and so forth) are marked on the flat upper face ofthe base.

The various uses to which the instrument shown in Figs. 1 and 2 can beput will be understood from the following examples Example 1 It isdesired to determine the force and direction of the wind fromobservations made from an aeroplane flying over uncharted country orover the sea.

The operations to be performed by the observer are as follow":-

One of the arms d or cl is set to a position on the circular scalecorresponding to the compass course steered by the air craft, the re"spective cursor e or e is then set to the position on the armcorresponding to the air speed of the aircraft as shown by the air speedindicator, and the corresponding blade g or g is set to the positioncorresponding to the drift angle as observed by any convenient means.The clamping screws f and h or fare then tightened.

The navigator now alters the course through a small angle and sets theremaining arm, cursor, and blade to the positions corre sponding to thenew compass course, air speed, and drift angle respectively.

Arm m and cursor Z are then adjusted until the clamping screw 27ctouches the two blades 9 and g. The speed of the windcan now be readdirectly from the position of the index mark of the cursor Z on thescale of the arm m, and the direction of the wind from the position of mon the compass scales on the ase a.

Example 2 It is desired to determine the compasscourse to be steered andthe ground speed to be made good to maintain a given ground course. k

i The force and direction of the wind having been obtained, either bythe method described above or from meteorological or other information,received, the arm m and cursor Z are clamped in their correspondingpositions-by their respective clamping screws n and 1c. Arm (1 is thenset to the position corresponding to the ground course to be made goodand is clamped by the screw 0 Cursorr'is moved to the position 011 thearm (1 corresponding to the air speed. The compass course to. be steeredis then read from the position of arm 9 and the ground speed madeposition of the cursor s on the arm d I Y Y In the "apparatushereinabove described the positions of the arm m and cursor Z are if;determined by bringing the screw into contact with theblades g and 9,

but the velocity and direction of the wind may be obtained,

and also to combine at .w in Fig. 5.

pilot desiring if desired, by sighting directly past the intersectionsof the said blades on to a scale on the arm m, or directly on tocircumferential and radial graduations on the base a. g

It is possible to combine either of the arms (Z or cl with the arm 51 ina single element, the degree scale on cursor c or c" with the-arm Q or din a single element, and to so arrange the parts that when the arms,cursors, orindex marks representing known quantities, are set to thecorre sponding graduations of their respective scales, the elementsrepresenting the whole of the remaining quantities are automaticallycaused to assume positions enabling the values of these remainingquantities to be imi-nediately and simultaneously read olffrom theirrespective scales without any necessity for further manipulation.

These advantages are obtained with the modified construction shown inFigs. 3-5

iliary arm pivoted. on the cursor (1 of Fig. 1 is here shown in the formof a pivoted extensible link consisting of the parts 9, g and g; ofthese parts, 1 is cursor c and has above. the cursor a loop or stirrupbearing, an index mark working in conjunction with the drift scale oncursor c, the lower port of 1 having a slot for the reception of thestraight hollow telescopic men'lber which itself receives the telescopicmember g" pivoted to pivot l: on cursor l. The construction ensures thatthe angle shown on the drift scale on cl'u'sor c is always the anglebetween the. axis of the arm (1 and the line joining the pivots oncursors c and l irrespective of the distance between these pivots.Alternatively, a non-extensible link may be used, pivoted on e andhaving a slot working on pivot L, as in Fig. 6. This sin'iplificationenables the values of the whole of the vector quantities represented bythe apparatus to be read oil from their respective scales without anynecessity for further manipulation, and also enables the whole of theparts 1), (Z, c, c, f, g, h to be entirely-dispensed with.

With this simplified form of the instrument the procedure to be. carricdout by a to obtain the force and direction of the wind. when flying overuncharted country is as follows Set arm 5 to the compass course steered;set cursor 1' to the air speed; set arm (I so that the reading on driftangle scale 11; agrees with the observed drift angle.

The pilot nmvalte'rs his course slightly and proceeds to: Set

arm (I to the new course; set

by a drift angle scale attached directly to the arm (1 and indicatedFurther, the blade or auxpivoted belovv the keeping q, 1' and d fixed,he rotates cursor e to the new air speed; and then, while arm m untilthe index mark on g agrees with the scale reading on-the auxiliary driftscale on 6, corresponding with the observed new drift angle.

The pilot can now read off directly (1) wind speed from cursor Z; (2)wind direction from arm m; (3) ground speed fromcursor s; ,(4) groundcourse from the arm d (by sighting through the opening in the arm on tothe scale on interior of the rim a) I and elements Z and m are leftfree,

' with. that of the base a but The following explanation will show howthe simplified construction enables the parts I), 0, d, e", f, g, h,referred to above, to be dispensed with. Referring to Fig. 1 supposingthat the arms q and 0Z are arranged diametrically opposite to oneanother, and that the cursors e and 7 are set to the same reading; alsothat the angle between the arms (1 and d is the same as the drift angleon cursor 6. Then, if cursor r and arm '9 are fixed, the pivot 70 willbe constrained to move parallel tathe arms g and d by reason of themathematical laws governing the operation of the pantograph. In otherwords, in some cases the arm g is redundant, and all the parts connectedtherewith and referred to above can be dispensed with. In all forms ofthe instrument, clamping devices may be provided for any of the movableelements.

Referring now to Figs. 6, 7 and 8, the form of thefinvention shownherein is adapted more particularly for use when it is necessary to makeobservations from an aircraft upon moving objects. The object may bemoving eitherupon land or water, or in the air, at a speed and in adirection capable of being readily ascertained but for the purpose ofillustration it will e referred to in the following description as thedatum ship.

In addition to the four arms 9, (1 m and (I, an arm y .is providedadapted to move about the central axis of the graduated base a andhaving a cursor 2. In this form the arm on is arrangedto rotateabout anaxis parallel displaceable relal tively thereto, while co-axial with theaxis of arm m is a circular degree'scale a which can be moved so thatsuccessive positions of with one another.

agiven diameter of the scale remain parallel The cursori on. the arm onis adapted to be connected with the cursors r,-s and e by a linkmechanism. The cursor e carries a degree scale arranged coaxially withthe pivot of the cursor and arm 01 carries a degree scale w concentricwith the axis of the base a. Alternatively, the degree scale m may befixed to the arm 9, as in Fig. 5.

To enable the required relativemotion of i the pivot i of the arm m tobe obtained this pivot is preferably arranged so as to work in a slotformed longitudinally in arm y or in the central hub 3/ of the arm asshown in Fig.

8. The pivot z is rigidly connected to the degree scale a and its lowerend is adapted to slide without rotating in a slot in a member 9' (Fig.8) which itself is constrained to have rectilinear motion only by meansof suitable guides' attached to the base a. The cur,- sor z is arrangedto move longitudinally along the arm 3 in unison with the pivot This.construction has the effect of so mounting the arm m that it is pivotedto and movable about the cursor z of the arm The graduated arms 9, d andd are preferably attached to, or formed integrally with, saddles orslides arranged to slide round the rim of the base a to which they maybe clamped by means of screws 0 0 and 0 respectively. An opening isshown near the outer end of each arm and may be provided with a sightingblade or wire for the purpose of enabling-the angular position of thearm to be determined either with relation to degree graduations formedon the fiat bottom of the base or "to degree graduations formed on theinner edge of the rim. The arm 3 is preferably located by means of a huby working in an opening in the base.

The cursors 1" and e may be clamped to their respective arms screws 0and frespectively. The link connection between the cursors may taketheform of a pantograph t bet-ween cursors 1', s and'l and of a slottedlink, or blade, or telescopic link g, which may or may not be graduated,between the cursors e and Z. If desired the cursor 8 may be arranged tobe disconnected from the link mechanism, either by withdrawing the pivotor by providing a slot for the reception of the pivot as shown. Aclamping screw 0 (Fig. 7-) may be provided to lock simultaneously thearm y, the cursor 2', and the degree scale a; an independent clampingscrew 0 (Fig. 7) may be. provided to clamp simul taneously the arm onand the cursor Z and the screw 0 (Figs. 6 and 7 may clamp the link orblade g.

The manner of using the instrument shown in Figs. 6-8 is as follows Byflying over the datum ship on two courses the observer in the aircraftwill be able to obtain observations of air speed, air course steered,and relative drift (that is to say, drift with relation to the datumship). T 0 work out the observations he first sets arm 1 and cursor z torepresent the course and speed of the datum ship, and clamps them. Hethen sets and clamps arm q to represent air course, cursor rto representair speed, and, by means of degree scale w, arm (I to represent relativeground course, on. one

course. Similarly he sets and clamps arm d and cursor e to represent aircourse and air speed respectively on the other course. Then,

the degree scale on cursor 6 shows the remaining relative drift angle.The arm m and the cursor I will then indicate the true direction andspeed of the wind. To obtain the true ground speed, it is now necessaryto clamp the wind elements m and Z, and to bring the destrumentcorresponds to that illustrated in Figs. 35.

If the instrument is required to indicate ground speed only, the arm mand the cursor Z in Figs. 3, 4 and 5 may be dispensed with.

. For certain purposes the instrument, as used.

in connection with observation of drift with ing arm end to the centreof the base.

regard to a datum ship, may be constructed Without the parts 0, d, e, f,g and c, in Figs. 6, 7 and 8. I

In all forms of the instrument shown in the drawings, and hereinabovedescribed, a number of arms are constrained in such a manner that eachmust always. lie along a radius drawn from the centre of the base. Thisre- ;sult may be achieved by .pivotin the inner .end or ends of any oneor more of he arms at the centre of the base or by mounting the outerend or ends of one or more of the arms on a sliding saddle such as thosedescribed above and indicated in the drawings at b, 6, b movin round acircular external rim or its equiva out, or by mounting the outer end ofone or more of the said arms on a supportwhich isitself pivoted at itsinner What we claim and desire to secure by Letters Patent is v i 1. Anavigating instrument comprising in combination, a graduatedcircularbase, three graduated arms, means mounting said arms so as toextend radially of but be movable about the centre of the base, a cursorslidable on and along each of the arms respectively, and a pantographicdevice interconnecting 1 thecursors and pivoted to each whereby thepoints of connection are maintained in a straight line, a fourth armradially extending from and rotatable about the common centre, avcursorslidable on and along said fourth between said scale and a piot point ofsaid pantograph on one of said three first-named cursors.

combination, a

' so as to extend radially of but be movable about the centre of thebase, a cursor slidable on and along each arm respectively, a degreescale attached to one of the arms and ararm, a drift scale pivoted onsaid cur.- S01, and a link connectlon ranged concentric with the base,an auxiliary degree scale on the cursor of one of the other arms, a.link connection between the cursors of all four arms, and clampingdevices for clamping the cursors and scales in desired positions.

3. A navigating instrument comprising in combination, agraduatedcircular base, three graduated arms, means mounting said arms so as toextend radially of but be movable about the centre of the base, a cursorslidable on and along each of the three arms respectively, a,pantographic device interconnecting the cursors and pivoted to each insuch a way that the points of connection are maintained in a straightline, a drift scale attached to one of said arms, a fourth arm, meansmounting this arm so as to extend radially of but be movable about thecentre of the base, a cursor slidable on and along the fourth'arm, adrift scale. mounted on this cursor, a link connection between a pivoton this cursor and one of the pivots of the pantographic device, andclamping devices for locking the arms and 'cursors in desired positlons.

4. A navlgating lnstrument comprlsing in combination, a graduatedcircular base, three graduated arms, means mounting said arms so as toextend radiallyof but be movable aboutthe centre of the base, a cursorslidable on and along each of the three arms respectively,

cursor slidable on and along the said fourth arm, a pantographic deviceinterconnecting the fourth cursor and two of the first-mentioned threecursors, means for disconnecting the pantographic device from thecursors at will, a degree scale on one of the arms carrying said twointerconnected cursors, a circular degree scale concentric with thefourth arm and mounted upon the cursor carrying this arm, means forguiding this circular degree scale so that a given diameter thereofalways remains parallel to itself, a fifth arm, meansmounting the sameso as to extend radially of but be movable about the centre .of thebase, a fifth cursor slidable on and along the fifth arm, a drift scale,mounted a fourth arm pivoted to and movable about one of the said threecursors, a fourth on this cursor, a link connection between the fifthcursor and the pivot common to the fourth cursor andthe pantographicdevice, and clamping devices for locking the arms, cursors", and scales,in the desired positions.

5. A navigating instrument comprising in combination, a graduatedcircular base, three graduated arms, means mounting said arms so as toextend radially of but be movable gbout the centre of the base, a cursorslidable. on and along each arm, a degree scale attached to one of thearms and arranged concentric with the base, a fourth arm .and a circulardegree scale mounted upon the cursor of one of the arms not providedwith the first-mentioned degree scale, means mounting the fourth arm onsaid lastnamed cursor so as to rotate about the centre of said circulardegree scale, means for guiding this circular degree scale so that whendisplaced by the movement of the cursor carrying the same successivepositions of a given diameter of the scale remain parallel to oneanother, a cursor slidable on and along the fourth arm, a linkconnection between this fourth cursor and the remaining two cursors, andmeans for disconnecting the link at will.

6. A navigating instrument comprising in combination a graduatedcircular base, three graduated arms, means mounting said arms so as toextend radially of but be movable about the centre of the base, a cursorslidable on and along each of the three arms respectivel-y, a fourth armpivoted to and movable about the third one of the said three cursors, afourth cursor slidable on and along the said I fourth arm, apantographic device interconnecting the said fourth cursor and the firsttwo of the first-mentioned three cursors, means for disconnecting thepantographic device from the cursors at will, a degree scale on oneof'the arms carrying the first and second cursors, a circular degreescale on the third cursor arranged to show the angular position" ofithefourth arm, means for guiding the said circular degree scale so that anydiameter thereof always remains parallel to itself, and" clampingdevices for locking the arms, cursors, and scales in desired positions.

In testimony whereof we affix our signatures.

HERBERT ADDISON. \VILLIAM BLAINE LUARD.

